BirdNote; Birds Are Evolving Rapidly - Today

BirdNote®

Birds Are Evolving Rapidly – Today

Written by Gordon Orians

This is BirdNote.

[Song of House Finch]

Many people think that evolutionary change occurs so slowly, we cannot observe it directly. Not so! For example today in the U.S., House Finches are evolving rapidly and visibly.

[Song of House Finch]

In 1941, some captive House Finches from California escaped near New York City. They spread rapidly and are now found across most of the United States and in southern Canada. Many of these areas have cold, snowy winters, during which many birds die. The finches have evolved, because those that survive differ from their parents. Size is one example.

[Cold winter wind]

Male House Finches in recently established populations in Michigan and Montana are larger than the males that escaped. Large males out-compete small males for food, so are more likely to survive the winter. They also pair more successfully with females early in the spring.

[Song of House Finch]

Smaller females survive better than larger females as nestlings. Also, because they need less food to maintain their own bodies, they can breed earlier in spring. Females that breed earlier raise more young than those that start breeding later.

[Chatter of several House Finches]

Rapid evolution of House Finches, reminds us that evolutionary changes are occurring visibly all around us.

For BirdNote, I’m Michael Stein.

###

Sounds of the birds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Song 105669 and call 44976 of the House Finch recorded by G.A. Keller.

BirdNote’s theme music was composed and played by Nancy Rumbel and John Kessler.

Producer: John Kessler

Executive Producer: Chris Peterson

© 2015 Tune In to Nature.org December 2014/2015 Narrator: Michael Stein

ID# evolution-02-2011-11-10